Detection of an atmosphere on a trans-Neptunian object beyond Pluto (opens in new tab)

The only trans-Neptunioan object (TNO) with a detected atmosphere so far is Pluto, which has an average surface pressure of 10 μbar. Investigations of other large (>500 km) TNOs have only been able to establish upper limits of 1–100 nbar. A recent near-infrared study reported methane gas emission from Makemake, although its origin remains uncertain. Here we report that a stellar occultation campaign performed on 10 January 2024 of the ~250-km-radius plutino (612533) 2002 XV93 reveals a refrac...